Topic: 1976 CB550F overhaul in France

[Connito]

Hello guys and gals,

Let’s hope the new year brings us lots of smiles, whether on the road or in the garage!

After a long time of searching for the “right” bike in France, I have finally acquired a 1976 CB550F in need of revitalizing. Of course, it needs much more than I originally thought. Don’t they always !
The list is long! I have rebuilt the forks already. The carbs are now ultrasonically cleaned and awaiting assembly. The calipers are already cleaned and awaiting assembly with new pistons. Yes, it has a double disk front brake. The motorcycle eventually will be painted Valley Green Metallic (CB 750 K1 color) and I will make a few other cosmetic changes to make it more to my liking. Exchange the turn signals to earlier smaller ones, swap the triple trees to CB750 K1, change the front fender to a double bracket one, relocate the ignition switch to the side etc. Basically, make it look a bit older. I will certainly not cut anything.

The biggest issue was/is the substantial oil leak from the head gasket. I removed the head and I was in for a surprise. The pistons have been changed, but apparently not by someone who knew what they were doing. (Actually, I have discovered this throughout the whole bike. Half tighten screws, some things started, but never correctly finished etc.) Anyway, the top rings were all broken in half! What is worse, is that I only have 7 halves… I don’t know if one of them dropped down the engine when I was removing the head, or...? I will have to remove the pistons anyway to clean them and the surface for the gasket. I will look down the engine then. The cylinders look good, and so are the pistons, in my opinion. I will take pictures when I remove and clean them. I believe that they are good, and I will need only rings, but I will ask your opinion when I have the pictures. I’d rather do this correctly and I am in no rush.
For some reason the wiring on the throttle side was out of the handlebar. The PO made a hole in the the bottom part of the switch assembly instead of thread the wiring through the handlebars  The wiring is now inside the handlebar, but I need the bottom part of the switch. Anyone has one?

Thanks for reading! I am sure I will have lots and lots of questions when the re-assembly starts!

Cheers,
Pete

[flatlander]

welcome from one blue '76 550F (short: 550F1) guy to another!
that looks like a nice enough starting point for a "conservative" restoration.

this thread will probably be super helpful for your work: http://forums.sohc4.net/index.php/topic,151576.0.html
and of course the honda workshop manual and partslist.

take off the oil pan and if you're lucky the broken bits are in there. if not then unfortunately you'll need to go search for them in the bottom end.
does it look like the bottom cases have been split (screws, gaskets can tell)? if so, based on what you found i'd personally open them up anyway.

[Stev-o]

welcome from one blue '76 550F (short: 550F1) guy to another!

+1...welcome to the Blue 550F club! [for the time being]

BTW - not seeing the pics.   PM sent on parts you are needing...

[flatlander]

the pictures disappeared for me, too. saw them earlier, though.

[rb550four]

  Oh No!  550 ghost pictures...can you see the bike's reflection in a mirror?

[bek1966]

Sounds like a fantastic project.  My son is in the process of buying a blue '76 550F (the PO is waiting for the title to come back from the DMV).  Looking forward to seeing your project and in particular the swap-out of the larger turn signals for the smaller ones.  Can't wait to see the pictures!

Brad

[scottly]

K1 750 triples are not compatible with a 550 frame; the stem is 20-23mm longer. They also have 10mm more offset than 550 triples.

[Alan F.]

It would seem to mount 750 triples all you'd need is a stepped bearing cup to raise the upper bearing race 20-23mm or lower the lower bearing race 20-23mm depending on the amount of trail you're trying to achieve.

This is either a simple solution or a terrible idea.

[Connito]

welcome from one blue '76 550F (short: 550F1) guy to another!
that looks like a nice enough starting point for a "conservative" restoration.

this thread will probably be super helpful for your work: http://forums.sohc4.net/index.php/topic,151576.0.html
and of course the honda workshop manual and partslist.

take off the oil pan and if you're lucky the broken bits are in there. if not then unfortunately you'll need to go search for them in the bottom end.
does it look like the bottom cases have been split (screws, gaskets can tell)? if so, based on what you found i'd personally open them up anyway.

Thanks a lot! The link will be super helpful!
Yes, I will definitely take off the oil pan. I sure hope I don't have to split the cases though. I haven't looked closely yet, but I don't think that the bottom has been touched.

[Connito]

Sounds like a fantastic project.  My son is in the process of buying a blue '76 550F (the PO is waiting for the title to come back from the DMV).  Looking forward to seeing your project and in particular the swap-out of the larger turn signals for the smaller ones.  Can't wait to see the pictures!

Brad

Good luck to your son! I will post updates for sure.

[Connito]

Thanks all for your replies! Weird about the pictures. I wanted to insert them rather than attaching them, as it is nicer to see and follow, but I guess Google Photos doesn't allow it, or there are some settings... Anyway, I am attaching them now here.

[Connito]

The pistons and the rings...

[Connito]

welcome from one blue '76 550F (short: 550F1) guy to another!

+1...welcome to the Blue 550F club! [for the time being]

Thanks! Yes, it will not be blue for long. I tried to like it! As soon as I found out that it was not the original paint, the decision was easy

BTW - not seeing the pics.   PM sent on parts you are needing...

[Connito]

K1 750 triples are not compatible with a 550 frame; the stem is 20-23mm longer. They also have 10mm more offset than 550 triples.

Thanks! Yes, I know they are not the same, but I was thinking to either have spacers as Alan suggested, or continue the thread and then cut the length of the stem. Will see when I get them next to each other. If it's too difficult (expensive) I may abandon the idea. I want to get rid of the ignition switch in the middle of gauges and relocate it to the side.

[rb550four]

   How do the cylinder walls look?
Are there any markings on the head from fragged parts hitting it or the valves?
   You may want to take those pistons out and do a thorough search for pieces/ parts after you take the pan off, while you are there, check the play on your primary chain and see if there is any ware at the bottom of the cam chain adjuster mounting area from a slack cam chain. If you see pieces/parts/case grindings from cam chain you will be splitting the cases for thorough cleaning to remove any metal shavings / fragments, replace slack chains and find the rest of those rings.
    Nice project for sure .
   

[Connito]

Does anyone have a the bottom of the throttle side switch unit? The Po made hole in mine.

Also, I believe that I need two of these things (sorry, I have no idea what are they called) like the one on the picture. It is located between the the bottom of the engine and the cylinders.

Speaking of the cylinders, Can someone tell me how to remove the old gasket? I tried with heat, soaking in gasoline and diesel. It jus doesn't go! The paint is really bad, so I may just buy another unit. What do you smarter people think?

[Connito]

   How do the cylinder walls look?
Are there any markings on the head from fragged parts hitting it or the valves?
   You may want to take those pistons out and do a thorough search for pieces/ parts after you take the pan off, while you are there, check the play on your primary chain and see if there is any ware at the bottom of the cam chain adjuster mounting area from a slack cam chain. If you see pieces/parts/case grindings from cam chain you will be splitting the cases for thorough cleaning to remove any metal shavings / fragments and replace slack chains.
    Nice project for sure .
   

Thanks for your reply! Yes, I will definitely remove the oil pan and the pistons and see what I can do. I will try to stay away from removing the engine and splitting the cases, but I will certainly do it if it's necessary. The wall of the cylinders look good. I couldn't take a better picture due to lighting, but I will and I will post it here.
Cheers,
Pete

[rb550four]

  Are  you talking about the rubber O rings to replace because what it surrounds and seals looks to be in OK condition. Those O rings will come in the new complete gasket kit that you will need to get... the other O rings and head gasket will also come in the complete kit withe everything else you'll need to seal the head . There are pucks ,  round seals to replace above the head that most kits don't come with and are sold separately,  order them at the same time if your kit doesn't include them.
  And, if you split the cases be sure to get the lower crankcase seals...they are  sold separately from the top end overhaul gasket kit ....because you'll hate to put the top end all together after splitting the cases  and find out the 40 year old gaskets are failing. Oh and no one wants to find silicone sealant on the 2 halves of the lower cases  or anywhere else on an engine, no telling what the squished out excess will get into to restrict oil flow at a later date and give you big issues. I use an aviation grade brush on form -a- gasket seal for the 2 halves only then leave it on the shelf after assembling the lower end.
   Rebuild lube, can't forget that , you'll want to have those clean parts lubricated for the first start up. This is the short list, don't worry though, it get's longer . But it's easier if you post your progress regularly especially if you need to know about any other parts that are known to ware to look for while you're in there. If you aren't sure about something just ask, someone is always here that can help .  The lower head gasket , always takes time to remove carefully ,I use a razor blade and haven't found a better way. And in that first picture of what you wanted 2 of, what is that jagged cast at your charging system case/ cover all about? As for purchasing another set of jugs because the paint isn't good....you may be getting a replacement jug that is in worse shape than the one you own, I have seen that others here have cleaned them up ultrasonically or vapor blasted with excellent results, I still steel brush them clean using paint thinner to cut the oils trapped in the fins , then repaint.

[Connito]

  Are  you talking about the rubber O rings to replace because what it surrounds and seals looks to be in OK condition. Those O rings will come in the new complete gasket kit that you will need to get... the other O rings and head gasket will also come in the complete kit withe everything else you'll need to seal the head . There are pucks ,  round seals to replace above the head that most kits don't come with and are sold separately,  order them at the same time if your kit doesn't include them.
  And, if you split the cases be sure to get the lower crankcase seals...they are  sold separately from the top end overhaul gasket kit ....because you'll hate to put the top end all together after splitting the cases  and find out the 40 year old gaskets are failing. Oh and no one wants to find silicone sealant on the 2 halves of the lower cases  or anywhere else on an engine, no telling what the squished out excess will get into to restrict oil flow at a later date and give you big issues. I use an aviation grade brush on form -a- gasket seal for the 2 halves only then leave it on the shelf after assembling the lower end.
   Rebuild lube, can't forget that , you'll want to have those clean parts lubricated for the first start up. This is the short list, don't worry though, it get's longer . But it's easier if you post your progress regularly especially if you need to know about any other parts that are known to ware to look for while you're in there. If you aren't sure about something just ask, someone is always here that can help .  The lower head gasket , always takes time to remove carefully ,I use a razor blade and haven't found a better way. And in that first picture of what you wanted 2 of, what is that jagged cast at your charging system case/ cover all about? As for purchasing another set of jugs because the paint isn't good....you may be getting a replacement jug that is in worse shape than the one you own, I have seen that others here have cleaned them up ultrasonically with excellent results, I still steel brush them clean using paint thinner to cut the oils trapped in the fins , then repaint.

RB, thanks so much for the advice and encouraging words!
The part on the picture, that metal cylinder with the rubber O ring. Don't I need two of these? I only had one, and I see a place for another one on the other side.

I will try removing  the gasket with a razor blade. I was hoping for some chemical product to help, but I suppose the razor blade alone will do. I thought about painting it, but I think I will leave it as it is. It would look strange if I only paint the jug. I will let it show its character:)
Thanks again,
Pete

[flatlander]

yes, you need two of those. and they are super important, as the oil that goes into the head goes through them.

for gasket removal, i use some solvent (benzine works) and a scraper. razor blade may be a bit fine, a sharpened chisel could work better. be careful not to scratch the aluminium surface.

[Connito]

yes, you need two of those. and they are super important, as the oil that goes into the head goes through them.

for gasket removal, i use some solvent (benzine works) and a scraper. razor blade may be a bit fine, a sharpened chisel could work better. be careful not to scratch the aluminium surface.

Thank you for your reply and advice!
What is this part called and where can I buy it?

I tried with benzine, but it doesn't seem to work. Scraper, is too thick, so I am using scalpel and a sharp knife. Very slow process! I am half way done
Cheers,
Pete

[flatlander]

have a look here, no. 3:
https://www.cmsnl.com/honda-cb550f1-super-sport-550-four-1976-france_model17115/partslist/E04.html#.X_xHxOlKjlw

this site has all the parts list for all the individual models. even if you don't buy from them they're a great source of information. you can also take the part numbers from there and do an internet search on them, to see where else they're available.

gasket removal... is slow and painful process. patience my friend, patience!

[Connito]

Thank you!!!

[Sano]

  Good luck on your project.  Looks like you have a good starting point.  I had the same condition on my rebuild with broken rings.  I don’t think it ran much after the bungled top end rebuild.  Apparently most missing pieces went out through the exhaust ports.  There was some minor pitting in the combustion chamber from the pieces bouncing around but nothing in the bottom end.  I always recommend a rebore and new cast pistons and rings for a street motor (David Silver Spares is a good source)  No need to spend big $$ on forged pistons, just mill .010” off jugs and head and match intake ports for cheap power.
  I would still recommend splitting the cases for primary chain replacement and replacement of  internal rubber bumpers and seals.  If you go this far you will end up with a tight and reliable motor for many miles.
  These are fantastic bikes when restored and upgraded in a few areas (like suspension and tires).  I have a Ducati that does everything better than the Honda but I still have more fun riding the Honda! 

[Connito]

Hi Sano,
Thanks for taking the time to write and for your advise!
While I understand that taking the engine out and replacing the chains and everything is the wise decision, due to lack of time and funds, I have deiced to not to.
I removed the oil pan, tilted the bike on one side and inspected everything to the best of my ability. It all looks well and I couldn't find any loose pieces. I will leave it as it is.
For the top end, I contemplated whether or not to got one size bigger, but the cylinders looked just fine and I didn't want to spend the money on honing them. I ordered new stock size pistons from Japan.
I am looking forward to the day I will be able to ride the CB550F. It looks easier to maintain and lighter than the CB750, which I am accustomed to. I too have had and have ridden modern bikes, which do everything better. But that's not the point here, is it . A modern Toyota Camry will outperform and old Corvette, at lest in handling and braking and likely speed. But which one would one rather drive?
Thanks again for your comments and good luck on your project!
Cheers,
Pete